Cushion for log-carriers



(No Model.)-

F. 0. KILGORE. CUSHION FOR LOG CARRIERS.

Patented Mar. 27, 1894.

comumr.

UNITED STATES PATENT OFFICE.

FREDERICK O. KILGORE, OF MINNEAPOLIS, MINNESOTA.

CUSHION FOR LOG-CARRIERS.

SPECIFICATION forming part of Letters Patent No. 517,222, dated March27, 1894.

Application filed February 16, 1893- Serial No. 46 2,576- (No model.)

To all whom it may concern:

Be it known that I, FREDERICK O. KILGORE, a citizen of the UnitedStates, residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented certain new and useful Improvements in Cushionsfor Log- Oarriages; and I do hereby declare the following to .be a full,clear, and exact description of the invention, such as will enableothersskilled in the art to which it appertains to make and use the same.

My invention relates to cushions or buffers for saw-mill log-carriages.

The carriages herein especially referred to, are those used in saw-millsfor feeding the logs to the circular or band-saws. As is wellknown, whenin use, these carriages are usually manned by several operators, whoride, to-and-fro, upon the same while at work. These carriages when thusmanned and loaded with logs, are of great weight. Inasmuch, as thereturn movement of the carriage from the saws, is all lost time, so faras work is concerned, it is very desirable that this return movementshould be accomplished as rapidly as possible. Hitherto, so far as I amaware, this rapid return movement of the carriage has been greatlyimpaired and restricted from the conditions imposed by the wooden orrubber bumpers hitherto employed. If the carriage be run at full speedto near the limit of its travel before throwing off the power, andreliance be placed on the wooden or rubber bumpers to stop the same, themomentum would be so great as to break away the bu mpers, break orstrain the carriage, dislocate the load and frequently cause seriousaccidents to the operators. To prevent such results, it has been thecustom for the operator,in control of the carriage, to slacken orslow-up the speed of the same before reaching the bumper. Great cautionis therefore required, and much time is lost in effecting the returnmovement of the carriage.

It is the object of my invention, to provide a buffing device, againstwhich the carriage may be run at full speed, and be stopped by thebufiing action of the buffing device, without violent jar or shockeither to the carriage or the buffing device.

My invention is illustrated in detail, in the accompanying drawings,wherein like letters refer to like parts throughout the several views.

Figure 1 is a side elevation, showing the truck portion of the carriage,provided with an extended buffer head, and the buffing device inposition for cooperation therewith. Fig. 2 is a front end elevation ofthe buffing device. Fig. 3 is a vertical central longitudinal section ofthe buffing device, taken on the line X X of Fig. 2; and Figs. 4 and 5are similar views to Fig. 3, showing a modified form of the buttingdevice.

A represents the floor line of the mill.

B are the track-rails for the carriage, and O is the log-carriagemovable over the same,

some parts of the carriage mechanism being omitted. The carriage O isprovided, at its rear end with a centrally located and rear- Wardlyprojecting buffer-head D. This buffer-head may be of any suitablematerial, but is preferably made of wood and provided with a cap 11 ofrubber or leather, to muflie the initial engagement of the same, withthe piston of the buffing device, as will presently appear. The buffingdevice is in the nature of an air or steam cushion, comprisingacylinder, andapiston working therein, the cylinder being rigidly securedto the floor A, at the limit of the carriages rearward movement, withits axis approximately in line with the longitudinal path of the bufferhead D on the carriage.

E is the cylinder open at its front end, and provided with longitudinallaterally project ing securing lugs or flanges e, which are rigidlysecured to supporting timbers F, rigid with the floor, by means ofstay-bolts G passing through perforations in the lugs e, the timbers Fand the floor A. The bolts may be secured by means of nuts, not shown,or in any other suitable manner.

H is an air or steam passage fitted with a check-valve h, located at therear lower end of the cylinder E, adapted to prevent the escape of airor steam therethrough, from the cylinder and to permit the passage ofair or steam into the cylinder under the action of the suction of thepiston-head on its return or outward movement to normal position, aswill presently appear.

K is the piston head, as preferably constructed, provided with a rod orstem K,pro-

jecting rearward from the head K and working through a seat orperforation in the rear end of the cylinder. The stem K is provided, atits outer rear end with a stop K in the form of a screw threaded nut,which stop limits the forward movementof both the pistonhead and stem.

L is a retracting spring bearing against the inner face of the cylinderhead and acting against the back of the piston to throw the same intoits outermost or normal position. The spring, as shown in Fig. 3,encircles the piston-rod K, but is of larger diameter than the rod andis held in position and properly centered by spuds K projectinginwardfrom the piston and cylinder heads. These spuds would hold the spring,even if the piston rod should be dispensed with.

It should be noted, as an iinportantfeature of the construction, thatthe bu ffer-head D on the carriage, is much less in diameter than thepiston head K, against which the head strikes in the bufiing action. Invirtue of these relative dimensions, the buffer-head D does not requireto be fitted oraccurately set; and if, the carriage body should shiftlaterally on its truck or otherwise, it will make no materialdifference. The buffer-head will still strike somewhere on the face ofthe piston.

The operation is evident. Near the limit of the rearward movement of thecarriage,

'the buffer-head D comes into contact with the piston-head K of thebuffing device and forces the same rearward, thereby tightly closing thecheck-valve h and compressing the volume of air confined in the cylinderback of the pistorrhead. At first, the recession of the piston head willbe comparatively rapid; but the movement of the piston will be retardedwith an increasing resistance from the compression of the air confinedin the cylinder. Vhen the carriage is again moved away from the buffer,the compressed volume of air in the cylinder, it the pressure remainstherein, will tend to throw the piston head forward into its normalposition; but it is obvious that more or less leakage will, in time, bepermitted through the variousjoints, as forinstance, around the pistonhead K, or through the seat of the piston rod K and therefore it willnot do to rely on the air in the cylinder, for the return of the piston.The spring L is therefore provided to insure the positive return of thepiston-head into its normal position; and a fresh charge of free air ispermitted to enter through the air inlet H, and the check-valve h, aspreviously stated.

It is evident that the piston-rod K might work through a stuffing-box inthe cylinderhead, to prevent leakage at that point, if deemed necessaryor desirable.

Referring to the modification shown in Fig. 4, the cylinder-head is madesolid, the pistonrod is dispensed with, the spuds K serve of themselvesto hold the spring and the outward movement of the piston is limited bya suitable stop or stops, such for example, as an annular flange m,fixed to the outer end of the cylinder. Otherwise, the construction andop eration are the same, as the device shown in Figs. 1, 2, and 3.

Referring to the modification shown in Fi 5, an air-cushion in the formof adash-pot, is illustrated, with the piston P, secured to the end ofthe carriage C, and the bell-mouthed cylinder P, secured in a fixedposition near the rearward limit of the carriages travel, in line withthe piston P. The head of the piston P, is shown as provided withair-passages 1), covered by flexible valves 13, arranged to close theair-passages on the rearward movement of the piston P, and to open thesame on the return or outward movement of the piston. This, of course,prevents the escape of air from the cylinder in the butting action andpermitsa free entrance of the air behind the piston on its outwardmovement, thereby avoiding the suction, which would be caused by; thepartial vacuum produced behind the piston on its outward movement.\Vithout this or some other form of valve, to permit the inlet of air onthe outward movement of the piston, a partial vacuum would be caused, onaccount of the necessary leakage around the piston head in the buflingaction.

In all the constructions shown,the cylinder has been shown as in thefixed position, and

the buffer-head or piston, as carried on the carriage. Butit will beunderstood, ofcourse, that the relative positions of these parts, mightbe reversed. In other words, the cylinder might be carried on thecarriage and the co-o peratin g buffer-heads or piston, as the case maybe, be secured in the fixed position in the path of the moving cylinder.It is equally obvious, that with the form of the device shown in Figs. 3and 4, the piston-head K, might be provided with an outwardly extendedprojection, which would take the place of the buffer-head D and receivethe stroke directly from the end of the carriage. The two forms of valvemechanism shown might be substituted, the one for the other, or anyother suitable form of valve be provided in place of either form shown.

With the use of a cushion buffer, constructed in accordance with myinvention, the log-carriage may be returned at high speed and be quicklystopped by the buffer, without jar or shock. It may even be run at fullspeed against the buffer, but the carriage driving power must, ofcourse, be thrown off either coincident with or slightly before contactwith the buffer.

The amount of care or caution required in operating the log-carriage isgreatly reduced, the liability to accidents to the operators from thebufiing jars is removed, and the capacity of the circular or band-saw isgreatly increased by the gain made in the time required for the returnmovement of the carriage.

For some reasons, it may be more desirable IIO to use steam than air, asthe elastic medium for compression. Steam would be better than free airfor the reason that it might be held at any desired pressure; and theinitial check or resistance to the carriage could therefore be made ofany desired amount. On all the forms of the device shown, except thedash pot illustrated in Fig. 5, steam may be applied by simply couplingon a steam supply pipe to the inlet H.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is as follows:

1. The combination with a log-carriage, of the elastic fluid cushion,and cooperating buffer surface, one of which parts is carried on thecarriage, and the other is fixed in the path thereof, the said fluidcushion comprising a cylinder provided with air openings at its forwardend, and fitted with a piston for receiving the buffing stroke, a springbehind the said piston for returning the same outward to its normalposition, and an air inlet to the cylinder, behind the said piston,fitted with a check valve, arranged to permit the said piston to workagainst a volume of fluid confined in the cylinder in the bufflngaction, substantially as described.

2. The combination with the log-carriage, of an elastic fluid cushionbuifer and co-operatingbuffing surface, one on the carriage and theother fixed in the path thereof, the said cushion buffer comprising anopen ended cylinder with fluid inlet fitted with a check-valve, a pistonworking therein against the confined fluid to receive the buffing strokeand a spring behind the piston for throwing the same into its outermostor normal position, substantially as described.

3. The combination with the log-carriage, of an elastic fluid cushionand a buifer-head, one on the carriage and the other fixed in the paththereof, the said cushion comprising a cylinder fitted with a piston toreceive the buffing stroke, the said buffer head being of relativelysmall diameter, as compared with the piston-head, substantially as andfor the purpose set forth.

4:. The combination with the log-carriage, having a projectingbuffer-head, of a co-operating elastic fluid cushion, in the path of thebuffer-head, at the return limit of travel, the said cushion buffercomprising a fixed cylinder with open front end and having an inletfitted with check-valve, a piston working in said cylinder against thefluid confined therein on the bnffing action, and a spring for returningthe piston head, the said piston-head being of large diameter ascompared with the cooperating buifer-head, substantially as described.

5. The combination with a log carriage 0 having an extended buffer-headD, of the fixed cylinder E having inlet H with checkvalve h, the pistonK, rod K with external stop K and the spring L, all arranged andoperating, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

FREDERICK O. KILGORE.

Witnesses:

J AS. F. WILLIAMSON, EMMA F. ELMORE.

